Francis' exacts words are. "I'm injecting you with a serum that activates any mutant genes lurking in your DNA." This is one of my few nitpicks I had with the Movie, I don't like that Wade just got injected with a Serum, and got random healing powers. The way they make it sound, he could have randomly gotten laser powers, because the treatment affects everyone differently. And then he would have probably still died, because it wouldn't have done anything to stop his cancer.
I hope a future sequel with eventually reveal that Killbrew was in charge of the workshop, and specifically chose Wade because of his terminal cancer, to recreate Wolverine's healing factor. And Francis basically just fed him false info about the treatment.